Antibodies reacting in immunofluorescence with the basal cell layer of rat forestomach (BCLA) have been detected in 36 of 121 (30%) hepatitis B virus (HBV)-mediated chronic liver disease (CLD), in 1 of 30 (3%) HBV-negative CLD, in 3 of 36 (8%) alcoholic liver disease (with no correlation with serum HBV markers), in 1 of 25 (4%) primary biliary cirrhosis, in none of 19 HBV-related HBsAg-negative CLD and 60 healthy blood donors. Of 352 hospitalized patients with miscellaneous diseases (including immunological conditions), the antibodies were found in four (1%).

In the 36 BCLA positive cases from HBV-mediated CLD, evidence of chronic delta infection was found in 34. The overall prevalence of BCLA in 68 delta cases was 50% (58% in chronic active hepatitis, 46% in cirrhosis), and in 28 delta negative cases was 4% (p < 0.00002).

BCLA of delta cases were mainly of the IgG class (38 of 41 sera), and high titers (up to 40,960) were found in the majority (66% >1:640).

The high titer BCLA has to be considered a marker of chronic delta infection in HBV cases.